Toughen Undead (3.5e Feat)

From D&D Wiki

Benefit: When you create an undead creature you may choose to add a bloodstone worth at least 50 gp to the material components of the spell. If you do, the undead creature is created with two extra Hit Die.

Special: You may choose to take this feat multiple times, each time it increases the number of Hit Dice this feat provides by 2. The material component cost does not increase, however.